DPF Info - All CR-TDI Owners Should Read This

[gaffer1986]

From my experience (which is nearly 70,000 miles so far using the car for driving tuition), the DPF doesn't passively or actively regenerate until it is 45% full.

So doing a load of motorway miles may not necessarily be clearing the dpf as the dpf will only start to clear itself when it is 45% full. So if you finish a motorway journey with the dpf 44% full, you only have a couple of miles before it will attempt regenerative actively or passively depending on what sort of driving you do. If you don't do long enough journeys for a period of about 1.5 hours the dpf light will come on then you need to take action very soon with a 40+mph drive with revs exceeding 2000 rpm or the glow plug light will come on and you will have to call you breakdown service.

I am yet to hear of a solution that you can put in the fuel tank to help clear the dpf so approach with caution.

The safest thing you can do is not drive the car at all, get the breakdown service to take you to your local seat dealer and have a forced regen done or you risk needing a new dpf which is over a grand.

My car regens every 130 miles or so, but it used to regen less when it had less miles on the clock.

Every mile you drive whilst the car is doing what it is doing is further risk to your dpf.

 

[BDF81]

Scary but informative!

Gaffer1986,

Thanks for the advice. I'm calling the Seat dealer first thing! Keeping all my fingers a toes crossed i'm still okay for a forced regen.

A bit concerned about the car beyond that though, cause like I said, on top of the drive from Devon I did a motorway drive last weekend, so at that rate I'll have to go out on the motorway twice a week.

Thanks for the help.

BDF

 

[gaffer1986]

How many miles has it got on the clock? I hear dpfs have an expected life of 70-120k miles. What I do is keep an eye on my revs at idle, it idles higher during regen and is noisier. When it is doing a regen I avoid short journeys and turning the engine off/on until the revs return to normal. It's not so bad for me because I'm on the road for 8-10 hours a day and when it regens I simply ask my customers to leave the engine on, it will happily actively regen itself around town if left on but takes about an hour. Regen takes about 20 mins on the motorway.

If you keep an eye on the idle rpm you'll start to learn what the dpf is doing and plan your journeys around it.

I'm going back to petrol now, diesels are too much hassle.

Sent from my HTC One S using Tapatalk

 

[gaffer1986]

Having said all that, I know someone who had a 2007 2.0 tdi Skoda Octavia Scout with the 140 BHP pd engine that had a dpf despite short journeys with the occasional motorway trip he never reported dpf problems and had the car for 5 years. I drove it a fair bit and never noticed any dpf regen from memory. I think that's the same engine as yours.

Sent from my GT-N5110 using Tapatalk

 

[BDF81]

Mines done 39,000. One of the reasons I bought it.

Seat can't see me till Monday but have said if I get it my break down service to get it to them tomorrow they will look before if they can. The guy sounded very friendly and sympathetic.

I'll let you know what happens as soon as i know. Thanks for your input!

 

[gaffer1986]

You're welcome.

Sent from my HTC One S using Tapatalk

 

[MJJJ1]

Just got my TDI FR on Sunday and left the dealers with absolutely no idea what a DPF was never mind how it worked!

Good read here, hopefully save mines from any issues in the future

 

[DEAN0]

Just got my TDI FR on Sunday and left the dealers with absolutely no idea what a DPF was never mind how it worked!

Sounds about right - stealers don't give a **** about the consequences as long as they get a sale.

Add to that the fact that the DPF is not covered under warranty ( unless it corrodes through the case ) and they are winning all the way to the bank.

 

[MJJJ1]

Yeah, managed to get a good bit of cash for my p/x so just wanted to get in and get out without too many questions on it haha!

Only got 1500miles on the clock so DPF should be safe for now

 

[asthpsw]

Nightflight, excellent info and very understandable how you've laid it out. I don't suppose you have the same level of technical info on how the EGR system(s) work on the CR Engine please ?....not so self explainatory as in the pre PD days. I have a CBAB Engine and not sure what EGR System(s) (ie HP & LP) it has, whether it has a Cooler on the LP side, Filter on the LP side etc......what criteria causes either one to be opened and closed

Paul

 

[shnazzle]

Nightflight, excellent info and very understandable how you've laid it out. I don't suppose you have the same level of technical info on how the EGR system(s) work on the CR Engine please ?....not so self explainatory as in the pre PD days. I have a CBAB Engine and not sure what EGR System(s) (ie HP & LP) it has, whether it has a Cooler on the LP side, Filter on the LP side etc......what criteria causes either one to be opened and closed



Paul

It's one of the simplest systems on the car:

Exhaust flows form the exhaust manifold into the EGR cooler.
EGR cooler either cools the exhaust or bypasses it.
Exhaust goes from EGR cooler to EGR valve. EGR valve feeds into intake valve.

Cooler valve shuts if coolant is below 35C. So exhaust is not cooled and is passed straight to the EGR valve, which is open when the engine is cold so that everything reaches operating temperature quicker. If engine is at operating temp, the ECU-controlled EGR valve shuts gradually (has a Hall position sensor)

Coolant temp > 35C, vacuum valve on cooler is triggered, switching from bypass to cooler ducts and cooled exhaust is passed to the EGR valve. Same thing with EGR valve.

ECU decides whether the engine needs to burn less hot for a while by introducing less oxygen (as exhaust has less oxygen). this helps burn off nasty no-no's in the diesel exhaust.

Bob's your uncle.

Oh. There is no filter. Hence your EGR valve and intake flaps start looking like a tar pit after not too long.
EGR motor can seize, flaps can be ruined, much destruction. ...not really heard of this happening much on VW blocks though. Saab had a massive issue with it

 

[asthpsw]

Patrick, Hi and thanks, confirming then there is just one system ?.................I understood (but I don't know) that there is a High Pressure System (which was much the same as the original systems From the exhaust before Turbo then into inlert manifold...........but CR engines have a Low Pressure taken from after the DPF (& I thought a filter but maybe not) and depending on Engine Temp like you say can either go back into the inlet system this time before Turbo compressor. So as I say does this HP & LP systems exist on a CBAB engine and if so what would decide when the HP or LP System open (or indeed both closed)
Paul

 

[shnazzle]

Patrick, Hi and thanks, confirming then there is just one system ?.................I understood (but I don't know) that there is a High Pressure System (which was much the same as the original systems From the exhaust before Turbo then into inlert manifold...........but CR engines have a Low Pressure taken from after the DPF (& I thought a filter but maybe not) and depending on Engine Temp like you say can either go back into the inlet system this time before Turbo compressor. So as I say does this HP & LP systems exist on a CBAB engine and if so what would decide when the HP or LP System open (or indeed both closed)

Paul

Hmm...not aware of a HP feed tbh. Not sure it is different on any of the 2.0 CR engines. Do you mean it takes the post-DPF pressure sensor into account? If so, yes. All of that feeds into the ECU for it to decide on how much EGR to do.
The feed into the EGR cooler comes straight from the exhaust manifold from what I recall. The EGR cooler wouldn't cope with the temperatures of the turbo exhaust. Your coolant would boil I would think

 

[asthpsw]

Patrick, thanks again,

Have a look at http://www.dieselnet.com/tech/engine_egr_sys.php#components under light duty diesels and the explaination of figure 4................this is 2009 VW 2.0L engine...........but this is a USA version so is the European ERG very different ?

That's my question in the first instance re a European CBAB Engine.


Paul

 

[shnazzle]

Patrick, thanks again,



Have a look at http://www.dieselnet.com/tech/engine_egr_sys.php#components under light duty diesels and the explaination of figure 4................this is 2009 VW 2.0L engine...........but this is a USA version so is the European ERG very different ?



That's my question in the first instance re a European CBAB Engine.





Paul

Hey Paul. Very late reply sorry.
Not sure is the honest answer. The CR170 engines have modified cam setups for DPF regen purposes, but I'm not aware of them being used to keep valves open for LP EGR purposes. Pretty sure this applies to the CR140s as well (CBAB is in the same parts code range as CEGA).
Essentially all that does is keeps the exhaust valves open for a smidge and sucks air from the exhaust back up on the intake stroke. My MR2 does this, it's not great.


The EGR setup on the VW engines is more similar to, and in a small way different from,fig 3 on that page. There is no EGR exhaust valve on the VW engines. The EGR port is always open from the manifold. Its only when the EGR valve on the intake opens that it sucks air from the exhaust manifold, through the cooler (bypass or cooled) and into the pressurised intake.

You have got me thinking about the valves though...it's an old technology. You'd think VW has applied this as well. Mind, coincidentally I think it is an American/Japanese technique and that document you linked is US- based, and my MR2 is Japanese with Californian ultra-low-emission regulations....so it makes sense.
It's not EU emissions standard

Food for thought?
This is all from memory and what I've seen, but I think there are a few documents from VW's learning system "here and there". Might be worth looking for.

 

[DEAN0]

You have got me thinking about the valves though...it's an old technology. You'd think VW has applied this as well.

The elsawin workshop manual showing the cam belt change on the 140CR and 170CR TDi motors does not show any form of variable valve timing equipment attached to the cams/crank.

As far as I am aware - These motors do not have VVT technology fitted.

 

[shnazzle]

The elsawin workshop manual showing the cam belt change on the 140CR and 170CR TDi motors does not show any form of variable valve timing equipment attached to the cams/crank.



As far as I am aware - These motors do not have VVT technology fitted.

There ya go

Other than the lobe change for DPF functioning, no way it can keep the exhaust valve open longer unless the actually permanently change the cam lobes to so so. Which is stupid.

So safe to say EGR is "limited" to the valve-operated function controlled by ECU via various senders.

 

[asthpsw]

Deano, Hi, has this Workshop Manual got any diagrams of the EGR system fitted to the European engines by any chance ? (also what criteria...Engine Rev's, Engine Load, coolant temp etc that the ECU uses to open and close the EGR valve ?)

Paul

 

[shnazzle]

That's some very specific info you're after Precise ECU parameters.
To aid your search, the EGR amount is calculated based on:
- engine speed (G28)
- amount of fuel injected (ECU mapping param)
- airflow (MAF G70)
- air temp (G42)
- air pressure (not sure...calculated, or boost pressure sensor G31)

 

[DEAN0]

Deano, Hi, has this Workshop Manual got any diagrams of the EGR system fitted to the European engines by any chance ? (also what criteria...Engine Rev's, Engine Load, coolant temp etc that the ECU uses to open and close the EGR valve ?)

Paul

Elsawin says the following :

The engine control unit -J623- activates the exhaust gas recirculation system through the exhaust gas recirculation valve -N18- to the exhaust gas recirculation mechanical valve.
1. The mechanical valve for exhaust gas recirculation with conical tappet allows different apertures for different valve positions.
2. Thanks to stepped activation, the valve may be moved to any position.
3. The exhaust gas recirculation begins after the engine has been running at idle for 2 minutes.
4. Restart engine or briefly increase engine speed above 1,500 rpm when longer checks are necessary. Repeat the measurement.
5. For the further improvment of the exhaust emission values, the exhaust gas recirculation system is equipped with a cooler that is connected into the engine cooling system.
6. Under certain operating conditions, the exhaust gases that have passed through the combustion chamber are directed to this radiator. In this way, the temperature of the exhaust gas is reduced thus reducing the temperature in the combustion chamber and improving the emission values.
7. The engine control unit -J623- determines when the recirculated exhaust gas is routed via the cooler. The control unit actuates a vacuum unit via the exhaust gas recirculation cooler change-over valve -N345-, and the vacuum unit in turn operates the change-over flap for the exhaust gas recirculation cooler.